摘要
种植部位骨量不足是临床种植治疗经常遇到的难题,直接影响种植修复的效果。上置法植骨术(Onlay bone grafting)可以增加牙槽骨的三维骨量,成为解决骨量不足的重要方法之一。目前的植骨材料种类繁多,虽然能解决不同程度的骨量不足问题,但各有优缺点。骨诱导活性材料(osteoinduction active material,OAM)是由去抗原牛松质骨为载体复合骨形态发生蛋白(bone morphogenetic protein,BMP)形成的一种植骨材料,具有良好的生物相容性以及骨传导、骨诱导双重特征,弥补了其他植骨材料的不足,已应用于临床骨科领域。但是国内外在颌面部onlay植骨方面的实验和临床研究尚未见报道。
本实验的目的在于探讨块状的骨诱导活性材料(OAM)onlay植骨的可行性及其成骨能力,研究植骨愈合的机制,为临床应用提供实验依据。
本实验用块状OAM进行兔下颌骨onlay植骨,自体胫骨移植作为对照组,观察植骨材料移植后成骨和骨量维持情况。结果发现:随时间的延长骨诱导活性材料(OAM)和自体骨均与宿主骨的界面达到骨性结合,而OAM通过骨诱导及骨传导双重成骨方式形成新骨,比自体骨更好的维持新增骨量。因此,可以作为自体骨的替代物应用于onlay植骨术中。
Background
The development of biomaterials and surgical techniques have contributed to promote the application of dental implantation, which has become one of the important methods for the restoration of partially and totally edentulous patients. An important factor to ensure the long-term success of dental implants is a sufficient volume of the bone at recipient areas. However, alveolar bone always defects as a result from teeth extraction, trauma, or inflammation and so on. Various bone augmentation techniques have been suggested to repair the inadequate bone volume of the residual ridge. At present, the main approaches in clinical practice include bone condensing and bone splitting, guided bone regeneration (GBR), distraction osteogenesis (DO), bone grafting, maxillary sinus floor lifting. Onlay bone grafting is one of the important bone augmentation technology, which fixes the bone substitutes on the surface of the alveolar bone to increase width and (or) height of the maxilla and mandible, which can increase bone quantity significantly, and carry a lower rate of complications.
Onlay bone grafts were applied to oral implantology field in the early 1990s to recover the volume of the bone defect sites, which guaranteed the success rate of dental implants. Currently, bone substitute materials mainly include autografts, allografts, xenografts and artificial synthetic bone grafts. These different materials can solve the problems in bone defects, but have their own advantages and disadvantages respectively. Autografts are considered the“golden standard”for bone graft in terms of their osteoconductive, osteoinductive and osteogenic, but it has some weak points such as limited sources, needing to open the second operative area, great traumatic, so their clinical appliance is limitted. Allografts exist immunological rejection and the dangers of spread infectious diseases. Most synthetic bone grafts are nonbiological materials, and lack of osteoconductive activity, absorbed degradation obstacles the osteogenesis. Bone substitutes are divided into granular materials and block by their shapes. Granular bone graft materials have some weaknesses such as difficult plastotype, easily shifting to spread, maintaining alveolar ridge forms unsatisfactoryly, poor mechanical stability, osteonecrosis and wound easily occurs as result from granular moving, thus, their clinical applications are limited.
Osteoinduction active material (OAM) is a new kind of bone graft materials which is prepared by antigen-extracted bovine cancellous bone as a carrier combined with bone morphogenetic protein (BMP). It has excellent biocompatibility and good osteoinductive and osteoconductive capability. The three-dimensional network structure of bovine cancellous bone is considered as a scaffold which plays a role of conductive ability, which is both much efficient in releasing BMP and effectively guiding bone regeneration, also it has good biodegradability and the rate in step with bone formation, can not affect bone plasticity. In bone nonunions, bone defect, and fracture etc have achieved satisfactory clinical effects. However, there are not any reports about the use of massive OAM as an onlay bone graft material in mandibles.
Objective
The purpose of this study is to investigate the feasibility of block OAM as an onlay bone graft in rabbit mandibles, to evaluate its bone regenerative capability and the ability of bone volume maintaining, to discuss the bone formation mechanism in bone grafting.
Methods
Nine healthy Japanese white rabbits were used for the study with an average weight of about 2.5-3.0 kg and regardless of sex. They were randomly divided into 3 groups and 3 animals in each group, based on the time they were to be euthanized at 4, 8 and 12 weeks after bone grafting. The mandibles of each rabbit were divided into experimental groups and control groups at random. Experimental groups: OAM block + titanium screw + collagen membrane; Control groups: autologous tibia+ titanium screw + collagen membrane. Under general anesthesia, the skin, subcutaneous tissue and muscles were incised along the border of the submandibular region to expose the buccal of mandibular body and make surface roughness. OAM, and autologous tibia were implanted as onlay grafts in each side of mandibles at random, the graft materials in the form of a 5mm×5mm×2 mm cube, covered with collagen membrane, and fixed with titanium screws. The rabbits were respectively sacrificed at 4 weeks, 8 weeks, 12 weeks after bone grafting, and the specimens were collected for X-ray and histopathology analysis. Then, we evaluated the healing of grafts-host interface through the observation, new bone formation and maintaining in the bone height.
Results
All wounds were healed well after operation, and no postoperative infections and immunological rejection were observed in bone graft area and donor site. Except for one moved limp, others could leap without any pathologic fracture or limitation. Experimental samples, the extend of combination between OAM and host bone interface increased with the time, the stability of bone graft materials decreased ,without any moved in 12 weeks, while in the experimental group, absorption of OAM reduced slightly, in Control group, autogeneous bone absorbed and lost severely.
X-ray showed that there was a radiopaque shadowgraph in the OAM-host bone interface of experimental groups at 12 weeks, callus formation, and density were the same with the host bone density. At 8 weeks, the control group had no obvious boundaries between them, but absorbing seriously.
Histological observation showed that at 8 weeks after surgery, in the experimental group , a few of host bone grew into OAM , new bone connected with both, osteoblasts were rich, and there were plenty of angiogenesis, the biodegradation occurred and obviously degrade lacunae could be seen. In the Control group, grafting materials absorbed severely. At 12 weeks, in experimental group, there was good osseointegration between the OAM and host bone interface, which were thicker and more mature than at 8 weeks. New bone grew into the hole of OAM, which had lots of osteocytes in lacuna. OAM absorption was more severe than at 8 weeks, degraded into fragment, the cavity could observed after degradation .In the Control group, absorbed obviously and the remaining host bone with the new bone together, could not be distinguished.
Conclusion
In this experiment, we used the massive OAM as an onlay bone graft material in rabbit mandibles for the first time, and disscused the osteogenetic mechanism after transplantation. We drew the following conclusions:
1. OAM block is connected with the host bone in the term of osseointegration in experimental study.
2. OAM has biodegradability, and can maintain better bone volumes of augmentation than control groups.
3. OAM has excellent biocompatibility, osteoconductive and osteoinductive osteogenesis ability, could be considered as a good substitute of autologous bone.
In conclusion, the OAM has excellent biocompatibility and osteoconductive and osteoinductive ability, which can be used as a kind of autogenous substitute materials in onlay bone grafting.
引文
[1] Joos U, Kleinheinz J. Recon struction of the severely resorbed (class VI) jaws: routine or exception [J].J Craniomaxillofac Surg, 2000,28(1):1-4.
[2] McCarthy J G, Schreiber J, Karp N, et al. Lengthening the human mandible by gradual distraction [J]. Plast Reconstr Surg, 1992,89(1):1-8.
[3] Simion M, Trisi P, Piattelli A. Vertical ridge augmentation using a membrane technique associated with osseointegrated implants [J]. Int J Periodontics Restorative Dent, 1994,14(6):496–511.
[4] Isaksson S, Alberius P. Maxillary alveolar ridge augmentation with onlay bone grafts and immediate endosseous implants [J].Craniomaxillofac Surg, 1992,20(1):2-7.
[5] Tamimi F, Torres J, Bassett D C, et al. Craniofacial vertical bone augmenta- tion: A comparison between 3D printed monolithic monetite blocks and autologous onlay grafts in the rabbits [J]. Biomaterials, 2009, 30(31):6318–6326.
[6] Giannoudis P V, Dinopoulos H, Tsiridis E. Bone substitutes: An update [J]. injury, 2005,36(3):S20-S27.
[7] Stellngsma K, Bouma J, Stegenga B, et al. Satisfaction and psychosocial aspects of patients with an extremely resorbed mandible treated with implant-retained overdentures.A prospective,comparative study [J].Clin Oral I mplants Res, 2003,14(2):166-172.
[8] Antonio B, Paolo V, Bruno O, et al. Deep-Frozen Allogeneic Onlay Bone Grafts for Reconstruction of Atrophic Maxillary Alveolar Ridges: A Preliminary Study [J]. Journal of Oral and Maxillofacial Surgery, 2009,67(6):1300-1306.
[9] Kim S, Kim S S, Lee S H, et al. In vivo bone formation from human embryonic stem cell-derived osteogenic cells in poly (d,l-lactic-co-glycolic acid)/ hydroxyapatite composite scaffolds [J]. Biomaterials, 2008,29 (8):1043-1053.
[10]陈鹏,毛天球.活性纳米羟基磷灰石复合胶原/聚乳酸材料应用于牙槽嵴扩增的研究[J].口腔医学研究, 2008,24(3):282-284.
[11] Duda M, Pajak J. The issue of bio-resorption of the Bio-Oss xenogeneic bone substitute in bone defects [J]. Ann Univ Mariae Curie Sklodowska Med, 2004,59(1): 269-277.
[12]刘超,周正国,孔庆海. Bio-Oss和邻近自体碎骨骨移植在牙种植术中的应用[J].徐州医学院学报, 2005,8(4):333-335.
[13]滕寿发,林月秋,徐永清.近交系猪皮质骨复合骨髓基质干细胞及BMP-2修复兔大段骨缺损的研究[J].中国骨肿瘤骨病, 2007,6(2):80-84.
[14] Urist MR. Bone formation by autoinduction [J]. Science, 1965, 150(698):893 - 899.
[15]赵明,王会信,周廷冲.重组人骨形态发生蛋白-2成熟在大肠杆菌中的表达及其诱导成骨活性[J].生物化学杂志, 1994,10(3):319-324.
[16] Saito N, Takaoka K. New synthetic biodegradable Polymers as BMP carriers for bone tissue engineering [J]. Biomaterials, 2003, 24,(13):2287-2293.
[17] Seeherman H, Wozney J, Li R. Bone morphogenetic protein delivery systems [J]. Spine, 2002,27(16S): S16-S23.
[18] Prockop D J, Azizi S A, Colter D, et al. Potential use of stem cells from bone marrow to repair the extracellular matrix and the central nervous system [J]. BiochemSocTrans, 2000,28(4):341-345.
[19] Ruhe P Q, Kroese-Deutman H C, Wolke J G C, et al. Bone induetive Properties of rhBMP-2 loaded porous calcium phosphate cement implants in cranial defects in rabbits [J]. Biomaterials, 2004, 25(11): 2123-2132.
[20] Li R H, Bouxsein M L, Blake C A, et al. rhBMP-2injected in a calcium phosphate paste (alpha-BSM)accelerates healing in the rabbit ulnar osteotomy model [J]. J orthoP Res, 2003,21(6):997-1004.
[21]侯勇.金世植骨灵植骨治疗四肢骨不连23例体会[J].中国基层医药. 2003,10(9): 866.
[22]马全平.重组合异种骨植骨的临床应用体会[J].临床医药实践杂志, 2004,13(1):47.
[23]田锟,佘小明,钱宁,等.骨诱导活性材料修复腭裂骨缺损的动物实验研究[J].中国口腔颌面外科杂志, 2007,5(6):456-460.
[24]赵旺,周子敬,刘维贤.富血小板血浆修复种植体周围骨缺损的实验研究[J].口腔医学, 2009,29(6):295-297.
[25] Lee S H, Choi B H, Kim H S, et al. Comparison of corticocancellous block and particulate bone grafts in maxillary sinus ?oor augmentation for bone healing around dental implants [J]. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2007,104(3):324-328.
[26]宿玉成.现代口腔种植学[M].北京:第二人民卫生出版社,2004.
[27] Rocchietta I, Fontana F, Simion M. Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review [J].J Clin Periodontol, 2008,35(8Suppl.):203–215
[28] Tadic D, Epple M. A thorough physicochemical characterisation of 14 calcium phosphate– based bone substitution materials in comparison to natural bone [J].Biomaterials, 2004,25(6):987- 994.
[29] Wang M. Developing bioactive composite materials for tissue replacement [J].Biomaterials, 2003,24(13):2133-2151.
[30] Urist M R, Mikulski A J, Nakagawa M, et al. A bone matrix calcification-initiator noncollagenous protein [J].Am J Physiol, 1977,232 (3):C115-C127.
[31] Berggren A, Weiland A J, Dorfman H. The effect of prolonged ischemia time on osteocyte and osteoblast survival in composite bone grafts revascularized by microvascular anastomoses. [J].Plast Reconstr Surg, 1982,62(2):290-298.
[32] Jingshi S, Urabe K, Okazaki K, et al. Intramuscular bone inductionby human recombinant bone morphogenetic protein-2 with beta-tricalcium phosphate as a carrier: in vivo bone banking for muscle-pedicle autograft [J].J Orthop Sci, 2002;7(4):490-494.
[33]罗卓荆,胡蕴玉,吕荣,等.块型重组合异种骨的诱导成骨活性实验研究[J].第四军医大学学报, 1996,17(6):468-469.
[34]田锟,佘小明,钱宁,等.牛松质骨植骨体复合骨形态发生蛋白修复贵州小型猪下颌骨缺损[J].中国组织工程研究与临床康复, 2009,13(16):3037-3040.
[35] Schliephake H Bone growth factors in maxillofacial skeletal reconstruct- tion [J].Oral Maxillofac surg, 2002,31(5):469-484.
[36]赵旺.骨诱导活性材料修复犬种植体周围骨缺损的实验研究[D].沈阳:中国医科大学,2007.
[37] Carlisle E , Fischgrund J S. Bone morphogenetic proteins for spinal fusion [J].Spine J, 2005,5(6 Suppl):240 - 249.
[38] Jovanovic S A, Hunt D R, Bernaed G W. Long-term functional loading of dental implants in rhBMP-2 in duced bone. A histologic study in the canine ridge augmentation medel [J].Clin oral ImPlants Res, 2003,14 (6):793-803.
[39]卢旻鹏,蒋电明,权正学.判断骨移植材料-骨界面愈合的方法及标准[J].生物骨科材料与临床研究, 2008,5(4):24-27.
[40] Lane J M,Scandhu H S. Current approaches to experimental bonegrafting. [J]Orthop Clin North Am, 1987,18(2):213-215.
[41] Santoro F, Maiorana C, Rabagliati.Long-term results with autog- enous onlay graft in maxillary and mandibular atrophy [J].J Long Term Eff Med Implants, 1999,9(3):215-222.
[42] Bell R B,Blakey G H,White R P, et al. Staged reconstruction of the severely atrophic mandible with autogenous bone graft and endosteal implants [J].Oral Maxilofac Surg, 2002,60(10):1135- 1141.
[43] Adeyemo W L, Reuther T, Bloch W, et al. Healing of onlay mandibular bone grafts covered with collagen membrane or bovine bone substitutes: A microscopical and immunohistoch- emical study in the sheep [J].Int. J. Oral Maxillofac. Surg, 2008,37(7): 651–659.
[44] Cheng A C, Khin N T, Luen C S, et al. The management of a severely resorbed edentulous maxilla using a bone graft and a CAD/CAM-guided immediately loaded definitive implant prosthesis: A clinical report [J].The Journal of Prosthetic Dentistry, 2008,99(2):85-90.